Blank for producing a soft wall inside socket

ABSTRACT

A blank is described for producing a soft wall inside socket of a prosthesis having a pre-shaped side wall formed of a thermoplastic material, an inside liner and an outside sheathing. The blank forms a receiving space for receiving a shank stump and having an opening restricted by an edge of said side wall, for inserting the shank stump. For the purpose of adapting the height of said edge of the blank to the shank stump to be received, a slit-shaped recess runs along said edge and extends from the edge into the side wall by a predetermined depth (T). Preferably, the slit-shaped recess is arranged in the center of the side wall such that a double wall portion is formed with an inner wall adjacent to the inner liner and an outer wall adjacent to the outer sheathing, whereby the thickness of the inner wall essentially corresponds to the thickness of the outer wall.

BACKGROUND OF THE INVENTION

The present invention relates to a blank for producing a soft wallinside socket of a prosthesis comprising a pre-shaped side wall formedof a thermoplastic material, an inside liner and an outside sheathing,the blank forming a receiving space for receiving a shank stump or lowerleg stump, having an opening restricted by an edge of the side wall forinserting the shank stump.

Such a blank is known from the U.S. Pat. No. 4,635,626.

A blank for a soft wall inside socket is known consisting of athermoplastic material. The blank is pre-shaped such that it forms areceiving space having an opening restricted by an edge for receiving ashank stump. On the inner side of the receiving space a liner isprovided made of body compatible material. At the outer side a sheathingof wear resistant material is deposited. The liner and the sheathing aresewn to each other at the edge of the opening such that the edge isformed rounded. For individually adapting the blank to a shank stump ofan amputee the blank is heated to about 80° C. The blank is pushed ontothe shank stump and applied with excess pressure in a known manner.Thereby, the blank is precisely adapted to the individual shank stump.After cooling of the blank it keeps its form so that the soft wallinside socket is completed.

The above-described blank has the disadvantage that in a normallynecessary adaption of its length along the shank stump the edge cannotbe perfectly closed because of the thickness of the thermoplasticmaterial, which can lead to substantial drawbacks during wearing.

SUMMARY OF THE INVENTION

It is the object of the invention to provide a blank of a thermoplasticmaterial for producing a soft wall inner socket which can beindividually adapted in the length, and the edge of the receivingopening of which can be individually cut and formed rounded.

According to the invention a blank is provided for producing a soft wallinside socket of a prosthesis comprising a pre-shaped side wall formedof a thermoplastic material, an inside liner and an outside sheathing,the blank forming a receiving space for receiving a shank stump, havingan opening restricted by an edge of the side wall, for inserting theshank stump, wherein, for the purpose of adapting the height of the edgeof the blank to the shank stump to be received, a slit-shaped recessruns along the edge and extends from the edge into the side wall by apredetermined depth.

By providing the slit-shaped recess it is possible to adapt the heightof the edge to the individual shank stump and to connect thereafter theliner with the sheathing.

The invention also provides a blank wherein the slit-shaped recess isarranged in the center of the side wall such that a double wall portionis formed with an inner wall adjacent to the inner liner and an outerwall adjacent to the outer sheathing, whereby the thickness of the innerwall essentially corresponds to the thickness of the outer wall.Preferably the side wall is formed integrally and the material is athermoplastic foam material. Generally, the depth (T) of the slit-shapedrecess is about 2 to 4 cm and the width (B) is about 1/3 to 1/2 of thethickness (D) of the side wall.

A soft wall inside socket is formed of a blank, as described above, suchthat the height of the soft wall inside socket is adapted to the shankstump by cutting off a portion of the side wall, of the outer sheathingand of the inner liner, and that thereafter the outer sheathing isconnected with the inner liner. Preferably, the soft wall inside socketis adapted to the shank stump by cutting such that the outer sheathingand an outer wall portion, which is between the slit-shaped recess andthe outer sheathing, are shortened more than the inner liner and aninner wall portion, which is between the slit-shaped recess and theinner liner, are shortened.

Further features and advantages of the invention will be apparent fromthe description of embodiments with reference to the figures.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a soft wall inner socket produced from ablank;

FIG. 2 is a schematical side view along the line II/II in FIG. 1; and

FIG. 2a is the side view of FIG. 2 of the blank before the soft wallinside socket is formed.

DESCRIPTION OF THE INVENTION INCLUDING PREFERRED EMBODIMENTS

As can be seen from the figures, the blank 1 for a soft wall innersocket 2 comprises a side wall 3 pre-shaped of a thermoplastic foammaterial with a thickness D, being preferably in the order of magnitudeof 4 to 8 mm. The integral side wall 3 forms a receiving space 4 havinga receiving opening 5 for receiving a shank stump 6. The side wall 3 ispre-shaped such that the shank stump 6 to be received is surrounded. Thereceiving opening 5 is restricted by an edge 7. The run of the edge isadapted to a popliteal space of a shank stump amputee, and it comprisesa back portion 8 which contacts the popliteal space of the amputeeduring use. To the back portion 8 on both sides each a side portion 9 isconnected therewith which runs in an arcuate shape, as is shown in FIG.1, and sits close at the side of the knee during use. Both of the sideportions 9 are connected by a front portion 10 which sits close belowthe patella.

As can be seen in particular from FIGS. 2 and 2a, on the inside of theblank 1 an inside liner 11 is provided which is formed of a bodycompatible material. On the outside of the blank 1 an outer sheathing 12of wear resistant material is provided.

As is shown in FIG. 2a, a slit-shaped recess 13 is provided in the edge7 of the side wall 3 which extends around the whole edge 7 with a depthT of preferably 25 to 50 mm or 30 to 40 mm into the side wall 3. Theslit-shaped recess 13 comprises a width B of about 1/3 to 1/2 of thethickness D of the side wall 3. Because of the slit-shaped recess 13 theside wall 3 comprises a double wall portion at at the edge portionhaving an inner wall 14 and an outer wall 15 in parallel thereto, whichis formed in a U-shaped cross-section. The slit-shaped recess 13 isarranged in the center of the side wall 3 such that a thickness of theinner wall 14 corresponds essentially to a thickness of the outer wall15. The inner wall 14 comprises at the edge 7 a first front face 16adjacent to the inner liner 11 and the slit-shaped recess 13, and theouter wall 15 comprises a second front face 17 at the edge 7 adjacent tothe outer sheathing 12 and the slit-shaped recess 13. The first frontface 16 comprises a first edge 18 adjacent to the inner liner 11, andthe second front face 17 comprises a second edge 19 adjacent to theouter sheathing 12. Due to the dimensions of the slit-shaped recess 13the first edge 18 can be brought easily in contact with the second edge19.

For adapting the blank 1 to a shank stump 6 of an amputee the blank 1 isheated to about 80° C. At this temperature, the thermoplastic foammaterial can be shaped. The thus heated blank 1 is pushed over the shankstump 6 of the amputee and is applied from the outside with excesspressure. Thereby, the blank 1 is adapted to the precise form of theshank stump 6. After the blank 1 is cooled, it maintains its shape.Thereafter, the height of the edge is adapted by cutting off theportions of the edge 7 which are too high. To this purpose, the blank 1is taken off, and the first and second edges 18 and 19, respectively, ofthe inner liner 11 and the outer sheathing 12 are brought into contact,and the inner liner 11 and the outer sheathing 12 are sewn with eachother such that a rounded edge is formed. As an alternative, the innerliner 11 and the outer sheathing 12 and the inner and outer walls 14, 15may be bound by adhesive.

In a further embodiment, the outer wall 15 is shortened with the outersheathing 12 in a higher amount than the inner wall 14 with the innerliner 11 so that the sewn or adhesively bound edge 7 is inclined to theoutside as is shown in FIG. 1. Thereby, dressing and wearing of the softwall inner socket 2 is facilitated.

What is claimed:
 1. A blank for producing a soft wall inside socket of aprosthesis comprising a pre-shaped side wall formed of a thermoplasticmaterial, an inside liner and an outside sheathing,said blank forming areceiving space for receiving a shank stump and having a shank stumpreceiving opening restricted by an edge of said side wall, for insertingsaid shank stump, wherein, for the purpose of adapting the height ofsaid edge of said blank to said shank stump to be received, aslit-shaped recess is arranged in said side wall and runs along saidedge and extends from said edge into said side wall by a predetermineddepth (T).
 2. The blank according to claim 1, wherein the side wall isformed integrally.
 3. The blank according to claim 1, wherein thematerial is a thermoplastic foam material.
 4. A method of producing asoft wall inside socket from a blank of one of claims 1, 2, or 3 whereinthe height of the soft wall inside socket is adapted to the shank stumpby cutting off a portion of the side wall, of the outer sheathing and ofthe inner liner, and that thereafter the outer sheathing is connectedwith the inner liner.
 5. The method of claim 4, wherein said adaptationto the shank stump includes cutting such that the outer sheathing and anouter wall portion, which is between the slit-shaped recess and theouter sheathing, are shortened more than the inner liner and an innerwall portion, which is between the slit-shaped recess and the innerliner, are shortened.
 6. A soft wall inside socket which is produced bythe method of claim
 4. 7. A soft wall inside socket which is produced bythe method of claim
 5. 8. A blank for producing a soft wall insidesocket of a prosthesis comprising a pre-shaped side wall formed of athermoplastic material, an inside liner and an outside sheathing,saidblank forming a receiving space for receiving a shank stump and having areceiving opening restricted by an edge of said side wall, for insertingsaid shank stump, wherein, for the purpose of adapting the height ofsaid edge of said blank to said shank stump to be received, aslit-shaped recess is arranged in said side wall and runs along saidedge and extends from said edge into said side wall by a predetermineddepth (T), and wherein the slit-shaped recess is arranged in the centerof the side wall such that a double wall portion is formed with an innerwall adjacent to the inner liner and an outer wall adjacent to the outersheathing, whereby the thickness of the inner wall essentiallycorresponds to the thickness of the outer wall.
 9. A blank for producinga soft wall inside socket of a prosthesis comprising a pre-shaped sidewall having a thickness (D) and being formed of a thermoplasticmaterial, an inside liner and an outside sheathing,said blank forming areceiving space for receiving a shank stump and having a receivingopening restricted by an edge of said side wall, for inserting saidshank stump, wherein, for the purpose of adapting the height of saidedge of said blank to said shank stump to be received, a slit-shapedrecess is arranged in said side wall and runs along said edge andextends from said edge into said side wall by a predetermined depth (T),and wherein the depth (T) of the slit-shaped recess is about 2 to 4 cmand the width (B) of said slit-shaped recess is about 1/3 to 1/2 of thethickness (D) of the side wall.